Technical Field
The present disclosure relates to a transmission device, a transmission method and a transmission system. More particularly, the present disclosure relates to a transmission device, a transmission method and a transmission system using the unlicensed channel.
Description of Related Art
In general, a wireless communication system (e.g., the LTE system) runs in a specific RF (Radio frequency) spectrum, and an electronic device (e.g., a mobile phone) is able to communicate with a base station through the specific RF spectrum. The wireless telecom operators have to subscribe for or buy this specific RF spectrum from the government, so as to obtain the usage right of it.
In an entire transmission spectrum, some channels belong to unlicensed channels, e.g., some channels that the government retains. When the wireless telecom operators intend to use the unlicensed channels, they do not have to buy the usage right of the unlicensed channels from the government. Therefore, plural of wireless telecom operators (e.g, the Wi-Fi, the Bluetooth, or the LTE) compete for these unlicensed channels in order to obtain more transmission channels. For example, the LTE communication system establishes licensed-assisted access (LAA) protocol, enhanced licensed-assisted access (eLAA) protocol, and so on, which are used for standardizing the operations of the unlicensed channels in the LTE communication system.
However, in the process of the competition for the unlicensed channels, one device with one wireless communication system (e.g., the LTE communication system) has to coexist with devices with other wireless communication systems (e.g., the Wi-Fi communication system) that are not controlled by its wireless communication system. For example, when the LTE communication system intends to access an unlicensed spectrum or a shared spectrum of the wireless communication system, other communication devices with the same or different wireless access technique may intend to access the same unlicensed or shared spectrum. It can be seen that plural of devices may compete or interfere with each other when they share the unlicensed spectrum. Therefore, how to provide a method for sharing the wireless communication resource in the unlicensed spectrum and a device using the same becomes a problem.